Jarring tools



lnveni'or: RaP's MTLlrner Patented Sept, .9, 1958 JARRING TOOLS Ralph M.Turner, Washington, D. C.

Application June 11, 1956, Serial No. 590,759

3 Claims. (Cl. 1-47) This invention relates to new and usefulimprovements and structural refinements in jarring tools or percussiontools adapted for attachment to a conventional electric drill forconverting the rotary motion thereof into a reciprocating movement witha definite impact during each stroke, whereby the tool may beeffectively employed for driving nails and numerous other, similaroperations. More specifically, this invention is an improvement on myoriginal invention forming the subject matter of myV co-pendingapplication Serial No. 469,229, led November 16, 1954, now Patent No.2,749,548, issued June 12, 1956, of which this application is acontinuation-in-part.

While experimenting with the invention according to my earlierapplication, I found that thesame lends itself to various structuralsimplifications which result in greater economy of manufacture andgreater durability without impairing eiciency of operation, principalobject of the instant inventionfto provide a tool wherein suchimprovements are embodied.

With the above more important object and features in view and such otherobjects and features as may become apparent as this specificationproceeds, the invention resides in the arrangement of parts and detailsof construction substantially as shown in the accompanying drawing,wherein like characters of referenceV are used to designate like partsand wherein: v y

Figure 1 is a longitudinal sectional view of my improved tool;

Figure 2 is a fragmentary longitudinal sectional view thereof with thecam follower and shaft in the retracted position;

Figure 3 is a transverse sectional View, taken substantially in theplane of the line 3 3 in Figure l;

Figure 4 is a perspective view of the housing extension and cam memberintegral therewith;

Figure 5 is a group perspective view of the shaft, cam follower, adapterand sleeve used in the invention; and

Figure 6 is a perspective view of the work guide.

Referring now to the accompanying drawing in detail, the jarring tool isdesignated generally by the reference numeral 10 and embodies in itsconstruction an elongated housing 11 comprising a main body portion 12which is enlarged at one end thereof as shown at 12a to receive alconventional electric drill 13, the latter being secured therein by oneor more set screws 14. The housing 11 also includes an extension 15which is removably connected to the other end of the portion 12 by screwthreads 16.

-The extension 15 is formed integrally with a cam member 17 disposedwithin the housing, this cam member having lobes 18 with high and lowdwells 18a, 18b, respectively, as is best shown in Figure 4. Theextension 15 is also provided with inner and outer counterbores 19, 20,respectively, affording a bearing portion 21 therebetween.

A shaft 22 is rotatably and slidably disposed in the bearing 21, theouter end of this shaft having a work engaging face 23 while the innerend portion of the It is, therefore, the j, j

shaft is provided with an open-sided slot 24. Moreover, a transverselyextending cam follower 25 is formed integrally with the intermediateportion of the shaft and is operatively engageable with the cam member17. As is best shown in Figure 5, the opposite corner portions 26 of thecam follower 25 are rounded so as to facilitate their passage over thecam member lobes 18 in a sliding fashion.

rThe housing portion 12 is provided with a transverse partition 27having an aperture therein which affords a bearing 28 for a shaft-likeadapter 29, one end portion of the latter being engageable with thechuck 30 of the drill 13, while its other end is provided with asubstantially at, longitudinally projecting tongue 31. The tongue 31 isslidably but non-rotatably disposed in the aforementioned slot 24 of theshaft 22, whereby the shaft is rotatable with the adapter 29 and, at thesame time, may slide longitudinally relative thereto.

The intermediate portion of the adapter 29 is formed with a shoulder 32disposed at one side of the partition 27, while a snap ring 33 ispositioned in a groove 34 of the adapter at the opposite side of thepartition, to prevent the adapter from slidingin the bearing 28. It isto be noted that the partition 27 is provided with a eounterbore havingan oil seal 35 positioned therein, so that lubricant placed in thehousing cannot leak past the bearing 28 into the housing portion 12a.The housing portion 12 is vprovided with a suitable opening 36 tofacilitate insertion of a key to manipulate the drill chuck 30, and,also, to facilitate installation or removal of the snap ring 33.Lubricant may be placed in the housing upon removal of the housingextension 15.

In order to maintain the adapter 29 and the shaft 22 in axial'alignment, a tubular keeper sleeve 37 is positioned on the shaft so thatit extends over the slot 24 and the tongue 31. Y A relatively strongcoil spring 38, in turn, surrounds the sleeve 37 and extends between thepartition 27 and the cam follower 25, whereby to urge the latter inengagement with the cam member 17.

A relatively weak shock absorber spring 39 is positioned in thecounterbore 19 of the housing extension 15 on the shaft 22 and inengagement with the bearing portion 21, this spring also beingengageable by the Vcam follower 25 as will be hereinafter described. Theouter counterbore 2t) of the extension 15 slidably receives aprojectable and retractable work guide 40 of a tubular forni, the samebeing urged outwardly by a spring 41 in the counterbore 20, thisarrangement being substantially the same as in my Patent No. 2,749,548.The guide 40 is in surrounding relation to the work engaging face 23 ofthe shaft 22 and is retained in the extension 15 by an internal nut 42threaded as at 43 into the counterbore 20. As is best shown in Figure 6,the inner end of the guide 40 is provided with an outturned shoulder 44to abut the spring 41.

Having thus described the construction of the invention, its operationwill now be explained.

Assuming the tool to be in its initial position as shown in Figure 1with the cam follower 25 having its rounded corner portions 26substantially in alignment with the low dwells 18h o-f the'cam member17, rotation of the adapter Z9 and shaft 22 will cause the follower 25to ride along the cam lobes 18 with the result that the follower as wellas the shaft 22 will be retracted to the position shown in Figure 2wherein the follower engages the high dwells 18a of the cam member 17.At the same time, the spring 3S will be compressed, and as rotation ofthe shaft 22 continues, the follower 25 willl slide off the high dwells18a and under the action of the strong spring 38 will be drivenforwardly, thus correspondingly driving the face 23 of the shaft 22against the work. As is best shown in Figures 2 and 4, the cam member 17is provided between the adjacent high and low dwells of the lobes 18with recesses 45, which permit the follower 25 to be driven forwardly byinertia, beyond the low dwells 18b, so that the maximum forwardlyprojected position of the shaft face 23 is as indicated by the dottedline 46 in Figure l. The shock absorber spring 39 is of such length thatit does not become compressed until the follower 25 moves into therecesses 45 and, when the forward driving force of the follower isexpended, the spring 39 will automatically return the follower and theshaft 22 to its initial position as shown in Figure 1.

The guide 40, surrounding the work engaging face 23 of the shaft 22,will effectively prevent the tool from sliding or slipping laterally offthe work and, since the guide is retractable into the extension 15, ushdriving of a nail or other work will be facilitated.

The thread 16 connecting the extension 15 to the housing portion 12 ispreferably left-hand thread, so that it has the tendency to tightenitself by the rotating engagement of the follower 25 with the cam member17 of the extension 15. To avoid undue friction between the rotatingfollower 25 and the relatively non-rotatable spring 38, a suitablethrust bearing 47 is positioned in a recess 48 formed in the follower25, as is best shown in Figure 2.

While in the foregoing there has been shown and described the preferredembodiment of the invention, various modifications may become apparentto those skilled in the art to which the invention relates. Accordingly,it is not desired to limit the invention to this disclosure, and variousmodifications may be resorted to, such as may lie within the spirit andscope of the appended claims.

What is claimed as new is:

1. In a jarring tool, the combination of an elongated housing includinga main body portion adapted at one end thereof for attachment to anelectric drill and an extension provided at the other end of said mainbody portion, a cam member formed integrally with said extension anddisposed in said housing, a shaft extending rotatably and slidablythrough said extension and having a work engaging face at its outer end,a drill engagingV adapter rotatably mounted in said main body portion ofsaid housing, means slidably connecting the inner end of said shaft tosaid adapter for rotation therewith, a

cam follower provided intermediate the ends of said shaft andoperatively engaging said cam member whereby the shaft is reciprocatedduring rotation thereof, a coil spring provided in said housing andengaging said cam follower to urge the same against said cam member, anda shock absorber spring interposed between said extension and said camfollower.

2. In a jarring tool, the combination of an elongated housing includinga main body portion adapted at one end thereof for attachment to anelectric drill and an extension provided at the other end of said mainbody portion, a cam member formed integrally with said extension anddisposed in said housing, a transverse partition provided in the mainbody portion of the housing and formed with an aperture affording abearing, a shaft extending rotatably and slidably through said extensionand having a work engaging face at its outer end, a drill engagingadapter rotatably mounted in said bearing, means slidably connecting theinner end of said shaft to said adapter for rotation therewith, a camfollower formed integrally on an intermediate portion of said shaft andoperatively engaging said cam member whereby the shaft is reciprocatedduring rotation thereof, a relatively strong coil spring provided insaid housing between said partition and said cam follower for urging thelatter in engagement with said cam member, and a relatively weak shockabsorber spring interposed between said extension and said cam follower.

3. The device as defined in claim 2 wherein said means for connectingsaid shaft to said adapter comprise a projecting tongue formedintegrally with said adapter, the inner end portion of said shaft beingprovided with a slot having said tongue slidably but non-rotatablydisposed therein, and a tubular keeper sleeve positioned on andembracing the slotted portion of said shaft and said tongue whereby toassist in maintaining the same in alignment, said relatively strong coilspring surrounding said keeper sleeve.

References Cited in the le of this patent UNITED STATES PATENTS1,665,173 Misener Apr. 3, 1928 1,699,519 Brown Ian. 22, 1929 1,755,565Shook Apr. 22, 1930 2,657,383 Siering Nov. 3, 1953

